REVENUE - Commercialization Agreement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	$ 25,373	$ 20,617	$ 52,213	$ 41,534
Royalties and milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	542	$ 452	975	$ 859
Collegium Pharmaceutical Inc | Amended Commercialization Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	$ 11,300
Contract asset, amortization			1,800
Collegium Pharmaceutical Inc | Amended Commercialization Agreement | Royalties and milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues			$ 13,100